Painful diabetic peripheral polyneuropathy is a common, debilitating clinical problem for which there are no available therapeutic options that have been consistently effective in the long term. Gabapentin, a gamma-aminobutyric acid analogue anticonvulsant, has proven effective in treating painful peripheral neuropathy in some patients. Pregabalin is a more potent Gabapentin-like agent. Patients to be recruited into the study will have a history of one to five years of painful diabetic peripheral neuropathy. This is a phase II/III double blind, placebo-controlled multicenter trial. The objective of the study is to compare the efficacy and safety of pregabalin with placebo for symptomatic relief of the patients' neuropathy. Patients will receive pregabalin for six weeks, with the first two weeks as a titration period followed by four weeks of a fixed dose. Two hundred forty patients will be enrolled nationwide, with 8-20 at this site. Visits will include a history and physical examination, peripheral sensory examination and vision testing, questionnaires, and blood sampling. Outcome measures will be objective pain assessment and quality of life questionnaires.